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Helping to resolve the shortage of domestic water supplies in arid and semi-arid lands largely focuses on groundwater resources. A large proportion of the Afro-Asian dryland belt is not well served by geological mapping at suitable scales, i.e. better than 1:250 000. The area is enormous and the number of trained Earth scientists falls far short of requirements for adequate, conventional field mapping. H2Oexplore provides free learning resources about the use of remote sensing and GIS technologies to address geology, terrain and hydrology. They are based on the widely used textbook Image Interpretation in Geology [1]. Several case studies use a fully functional, free version of professional image processing and desktop mapping software. Geoscientists with access to a computer and the internet can independently study the standalone materials in office or at home using a wide selection of exemplary data.

Background theory is covered by six richly illustrated chapters. Chapter 1 covers the basics of hydrogeology. Chapter 2 is an introduction to remote sensing in the visible, reflected and emitted infrared, showing how the spectral properties of different surface materials can be used to design image processing and analysis strategies. Chapter 3 reviews the ‘traditional’ yet still highly effective use of stereoscopic aerial photography in terrain mapping and photogeology, using easily viewed stereo anaglyphs. Chapter 4 upgrades this approach to the wide-area stereo coverage available using ASTER data for several geologically well studied areas to demonstrate the relationships between terrain, rock types and structures in several study areas covered by published geological maps, and less well-known areas from NE Africa. Chapter 5 shows how the spectral approach introduced in Chapter 2 can be applied to multispectral Landsat and ASTER data, using various image processing strategies. It centres on a structurally complex area in central Eritrea that shows a wide variety of lithologies to demonstrate the mapping power of free Landsat and ASTER data. Chapter 6 covers digital analysis of topographic elevation data to extract accurate drainage networks useful in assessing surface water harvesting and aquifer recharge opportunities. These chapters are accessed individually through Contents or by downloading an eBook

A series of practical Exercises guide you through basic processes in the TNTmips Free software package (see Practical Learning Resources below), which are used to display and interpret image and terrain-elevation data. They are available as PDFs at the Contents page. The Exercises cover the basic tools that you will need to produce digital geological maps: displaying and enhancing image data; detecting different minerals; terrain and hydrological analysis; and digital mapping. They are based on data sets from a wide variety of study areas intended to encourage you to develop skills and experience in water-resource reconnaissance. An Appendix guides you through acquiring and preparing free image data of areas of interest to you so that you can use them in the free software package. Subject to a limited but still useful image size (1000 x 1000 pixels or 30 x 30 km using Landsat or ASTER data), completion of the Exercises and further practice should give you the skills to undertake small, water-related projects independently anywhere in the Afro-Asian dryland belt to a professional standard.

The learning resources are aimed at: geoscience professionals in national surveys; independent consultants; senior geology undergraduates and engineers working in the WASH/WatHab sections of NGOs and international agencies.

Note: Chapters 3 and 4 and the Exercises require you to be equipped with a simple red-cyan anaglyph viewer that can be obtained at low cost from several vendors, e.g. through eBay using search term anaglyph 3d glasses; at 3-D Market; at Paper Optics

TNT_2015_Doc_Win_20150624.exe (294 Mb) installs the TNTmips documentation, including a wide range of Tutorials for every aspect of the software. Most do not bear directly on the scope of the Exercises, but will help you develop a wide range of expertise, should you so wish. Whereas the TNTmips Tutorials are useful in their own right they are best used in conjunction with data sets that are intended for them that cover a very wide range of test areas and applications – TNT_2016_SampleData.zip (295 Mb)

The Exercises use a separate range of geological datasets that must be downloaded from Dropbox – data.zip (154 Mb)

For some users with poor Internet connection speeds (<2 Mbit per second) the file sizes may take a long time to download. In such cases the entire set of resources can be supplied on DVD by post, on request using the contact form below, remembering to include your postal address

Please note that I may make a small charge to cover costs of posting the DVD and a contribution to sending copies to people in less fortunate parts of the world. Currently that is UK£5 for residents in Europe and UK£9 elsewhere in the developed world.